Exercise device



FIG. 1 is a perspective view of an exercise device, showing my new design;

FIG. 2 is a front elevational view thereof, the rear elevational view, the top plan view and the bottom plan view being identical to this Figure;

FIG. 3 is a right end elevational view thereof; and,

FIG. 4 is a left end elevational view thereof. 

I claim the ornamental design for an exercise device, as shown and described. 